alert

The bank is alert to the danger.

该银行对这种危险有警觉。

Half of your brain stays alert and prepared for danger when you sleep in a new place, a study has revealed.

一项研究表明，当你在一个陌生的地方睡觉时，你的半边大脑会保持警觉并为危险做好准备。

He was still alert even in his eighties.

他80多岁时仍然敏捷。

"More sleep in old age, however, is associated with better health, and most older people would feel better and more alert if they slept for longer periods," he said.

他说：“然而，老年人睡眠时间越长，身体越健康。如果他们睡得时间更长一些，大多数老年人会感觉更好、更有精神。”

They should be alert to the possibility of fire accident.

他们应该认识到火灾发生的可能性。

He wanted to alert people to the activities of the group.

他想警告人们注意这个组织的行动。

For example, fear can alert us to possible danger.

例如，恐惧可以提醒我们可能存在的危险。